And I'm Kelly McEvers. Last night the New York Police Department confirmed that its controversial Demographics Unit has been disbanded. The special unit was created after September 11. It was devoted to tracking everyday activities in the city's Muslim neighborhoods.

New York Times reporter Matt Apuzzo won a Pulitzer Prize for his reporting on this unit. He's since co-authored a book about it called "Enemies Within: Inside the NYPD's Secret Spying Unit." Matt, welcome to the program.

MATT APUZZO: Great to be here.

MCEVERS: So what was this unit? What did they actually do?

APUZZO: Well, the Demographics Unit was a team of about a dozen detectives, plainclothes detectives, typically of South Asian or Arab descent. And they would get dispatched every day into Muslim neighborhoods and they would just hang out.

They had good language skills, Arabic or Urdu, and they would go out into a coffee shop or go for lunch and eat kabobs. And their job was to sort of look and listen. So the first thing they would do is they would go in and they would gauge sentiment - chat up the guy behind the deli counter at the halal deli and maybe get him to talk a little bit about politics, maybe see what he thought about, you know, drone strikes. So some of the files would talk about, you know, I observed two Pakistani men talking about the State of the Union Address and here's what they talked about. Those sorts of things.

MCEVERS: And the NYPD still does a lot of intelligence gathering. I mean just because this unit's going away, does it mean that these tactics are going to stop?

APUZZO: Well, right. I mean one of the things we're going to be looking for, and certainly one of the things the Muslim community is very concerned about is this was one aspect of a very broad intelligence gathering program, I mean where the NYPD designated entire mosques as terrorism enterprises. It allowed them to use informants, to audiotape sermons or to take license plates of everybody praying at mosques.

So I think we want to see, OK, well, what changes are going to get made. And this is really part of this kind of a broader theme of a reconsideration of the tactics that the country adopted post-9/11.

MCEVERS: I mean why was the unit closed in the first place?

APUZZO: Well, I mean I think it was closed for a number of reasons. One, in all the years of doing this, it never generated a single lead, never found a hot spot that led police to a budding terrorist. The other thing is, it just created a lot of weirdness. There were these peculiarities where police were going to restaurants a number of times, but not because there was a threat but because they really liked the food.

So if you served really good kabobs in Queens, you might actually get spied on more. And I think police saw that this was a real wedge between them and the Muslim community and that if they wanted to know where Muslims hang out, they could just go and say, hi, I'm from the police department, I speak Urdu, I'd like to know more about your community. I'd like to - here's my phone number.

MCEVERS: And what's been the reaction from Muslims in New York now to the closure?

APUZZO: Cautious optimism. I think there's a sense that this is a step in the right direction as far as they're concerned. There are still lawsuits pending over the broader intelligence tactics of the NYPD. Those will continue. I think the Muslim community feels like this is a good first step and they've really appreciated the conversations they've had with the police leadership, but they're not dancing in the streets at this point.

MCEVERS: Matt Apuzzo is a reporter with the New York Times and co-author of the book "Enemies Within." Matt, thanks so much.